They came out about the same time the MSD did. They get mixed results as does the MSD . Still a safe bet to go with the GM opti when needing to replace one. Just remember to locktite the rotor to prevent problems down the road.
I got one on "Wytltng". Been running for two years minus winter storage. Have had no problems. Reason I went used this compared to Delco was it was cheaper. I also use the ignition control box, coil, & module as well.